1. Field of the Invention
The present invention relates to a precision mask for deposition that is mainly used to form a hole transport layer, an emitting layer, and the like of an organic electroluminescence (EL) display, and a method for manufacturing the same. The invention also relates to the organic EL display, a method for manufacturing the same, and electronic equipment having the organic EL display.
2. Related Art
A conventional mask for deposition may be formed by wet-etching a single crystal silicon wafer of surface orientation (100) with potassium hydroxide or the like so as to reduce the thickness of the center of the wafer, and then by dry-etching the wafer to form an opening for deposition corresponding to each pixel of the organic EL display (see Japanese Unexamined Patent Application Publication No. 2001-185350, for example). The mask for deposition corresponds to the precision mask for deposition according to the invention.
A conventional mask for evaporation may be formed by wet-etching a single crystal silicon wafer of surface orientation (100) with potassium hydroxide or the like so as to reduce the thickness of part of the wafer, and by further wet-etching the wafer with potassium hydroxide or the like to form an evaporated pattern (an opening) (see Japanese Unexamined Patent Application Publication No. 4-236758, for example). The mask for evaporation corresponds to the precision mask for deposition according to the invention.
A conventional precision mask for deposition having a single crystal silicon wafer that is used for an organic EL display may include a plurality of elongated openings that are several dozen micrometers wide aligned as shown in FIG. 10. The openings make it possible to form pixels that are arranged lengthwise and each emit either red, green, or blue light.
The conventional mask for deposition having an opening for deposition corresponding to each pixel of the organic EL display (see Japanese Unexamined Patent Application Publication No. 2001-185350, for example) involves the following problem. It is necessary to align the mask for deposition with a glass substrate to which an emitting layer is evaporated within a tolerance of +/− five (5) micrometers both lengthwise and crosswise in a vacuum evaporation room. This hinders productivity.
The conventional mask for evaporation that is formed by wet-etching a single crystal silicon wafer of surface orientation (100) to form an opening (see Japanese Unexamined Patent Application Publication No. 4-236758, for example) also involves the following problem. If a plurality of elongated openings that are several dozen micrometers wide is aligned as shown in FIG. 10, part of the silicon wafer that is between two openings is too weak to withstand treatment. Thus, an evaporated wafer is not accurately patterned.
In consideration of these problems, the invention aims to provide a precision mask for deposition that is easily aligned with a glass substrate in evaporating an emitting layer and the like of an organic EL display, and is strong enough to form an accurate evaporated pattern. The invention also aims to provide a method for easily and accurately manufacturing such a precision mask for deposition, an organic EL display and a method for manufacturing the same, and electronic equipment including an organic EL display.